feat(pitch-deck): business model redesign + umlauts fix + tab animations

Business Model slide completely rewritten:
- Left: 3 pricing tiers (Starter/Professional/Enterprise)
- Right: Unit Economics (ACV, Gross Margin, NRR, Payback)
- Bottom-up sizing: 1,200 customers × 8,400 ACV = 10M ARR
- Land & Expand arrow visualization

Umlauts: 75+ ae/oe/ue → ä/ö/ü replacements across 10 slide files

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

pitch-deck/components/slides/FinanzplanSlide.tsx

@@ -369,7 +369,7 @@ export default function FinanzplanSlide({ lang }: FinanzplanSlideProps) {
               {rows.map(row => {
                 const values = getValues(row)
                 const label = getLabel(row)
-                const isSumRow = row.is_sum_row || label.includes('EBIT') || label.includes('Summe') || label.includes('Rohergebnis') || label.includes('Gesamtleistung') || label.includes('Jahresueberschuss') || label.includes('Ergebnis')
+                const isSumRow = row.is_sum_row || label.includes('EBIT') || label.includes('Summe') || label.includes('Rohergebnis') || label.includes('Gesamtleistung') || label.includes('Jahresüberschuss') || label.includes('Ergebnis')
 
                 return (
                   <tr key={row.id} className={`border-b border-white/[0.03] ${isSumRow ? 'bg-white/[0.03]' : ''} hover:bg-white/[0.02]`}>